Killing of Dendritic Cells: A Life Cut Short or a Purposeful Death?

Although we normally think of dendritic cells (DCs; references 1 and 2) as the “initiators” of immune responses and of their activity as confined largely to interaction with naive T cells in secondary lymphoid organs, there is emerging evidence that DCs are also important players in the effector phase of the immune response. Although rare, DCs form a dense network of cells in many tissues such as skin and respiratory and intestinal mucosa. This strategic location enables DCs to efficiently take up antigen and interact with effector CD4⁺ T cells in tissues to trigger cytokine secretion and activate local immune responses. Thus, we could envisage DCs in tissues as a true sentinel system with a dual mission: to alert T cells in the lymph node and trigger local defense reactions in nonlymphoid tissues. Although immature DCs, such...